Dental pin and dispenser

ABSTRACT

A dental pin for use in the reinforcement of restorations used in the reconstruction of mutilated teeth and a reinforcing rod and mandrel to be used in conjunction with the dental pin. A dental dispenser for handling such pins.

Unlted States Patent 1 1 1111 3,

Franklin et al. Apr. 1, 1975 [54] DENTAL PIN AND DISPENSER 2,472,1036/[949 Giesen 32/6 2, 4 [76] Inventors: Mark E. Franklin, 29 Koster Dr.,233 $222 I n Freehold, 7 James 3,473,223 /1969 Karlstrom 32/12 SchmIdt,33 Blrmmgham 3,675,328 7/1972 Weissman 32/15 Englishtown, NJ. 07726 22Filed; May 1 1972 Primary Examiner-Robert Peshock Attorney, Agent, orFirmKeny0n & Kenyon Reilly [21] App]. No.: 254,603 Carr & Chapin [52]U.S. Cl. 32/15 57 ABSTRACT [51] Int. Cl ..A61k 5/02 58 Field of Search7. 32/6 7 R A dental P for use the remforcement of restorations used inthe reconstruction of mutilated teeth and [56] References Cited e re1nf0rc1ng rod and nlandrel to be used In COl'ljUIlC- t10n wlth the dentalpm. A dental dlspenser for han- UNITED STATES PATENTS dling such pins400321 4/1889 Land 32/]5 1.216.683 2/1917 Greenfield 32/48 13 Claims,Drawing Figures PATENTED APR 1 I975 SHEET UlUF 10 QATENTEDAPR 1197s 3 .874,0 8T

sum new 10 'PEJENTEDAPR H915 3,874,081

SHEET UBGF 1O QATENTED APR 1 I975 SHEET Oh 0F 10 PATENIEDAPR H9753,874,081 SHEET U7GF 10 PATENTED APR 1 5 SHEET 08 0F 10 PATENTEU H9753.874.081

sum user 10 FIG. 42

FIG.4-3 FIG.44

DENTAL PIN AND DISPENSER BACKGROUND OF THE INVENTION 1. Field of theInvention This invention relates to the practice of dentistry and inparticular to apparatus for the reinforcement of restorations used inthe reconstruction of mutilated teeth.

2. Description of the Prior Art The preparation and reconstruction of amutilated tooth in dentistry has heretofore required a laboriousprocedure to restore the tooth to normal functioning condition. Suchpreparation and reconstruction often requires the use of reinforcementpins placed in the tooth structure and has had very limited success. Thelack of success of existing, conventional dental reinforcement pins isattributed to a number of factors. First, a two-step procedure isrequired, calling for drilling a hole in the tooth structure to receivea threaded, friction or cementable pin and then placing the dental pinin the hole. Second, there are voids between the pin and the toothstructure which form areas for entrance of impurities. Third, fracturesoccur at the threaded area of the tooth structure and such fracturesbecome greater when friction pins are inserted. Fourth, manipulation inplacing and positioning the pins is difficult and often results inbreaking the pin. Fifth, metallic or chemical bonding to the restorativematerial has not been achieved. Sixth, the entire procedure for dentalrestorations by use of reinforcement pins is of limited dentalapplication.

A great problem also exists in the control and use of the dental pinsthemselves. Dentists using these pins for restoring teeth havedifficulty controlling these items by the conventional pin forceps ordental pliers. The pins are small and, as a result, are often droppedand lost in the process of handling from the pin container to the dentalpliers or forceps and then to placement in the tooth. Most dentists donot attempt to recover the dropped pin, but start again with anotherpin. Even if the dropped pin were picked up, it would requiresterilization before it could be used.

SUMMARY OF THE INVENTION This invention relates to a newly designeddental pin, reinforcing rod and mandrel and to a newly designed dentaldispenser for handling such pins.

The newly designed dental pin and mandrel incorporates severaloutstanding features not found in existing dental pins. The dental pinof this invention is called an end cutting tube pin" and is designedwith end cutting blades enabling it to be seated in one operation.Several shapes and forms have been designed to achieve ease of seatingand manipulation.

The outstanding features of the end cutting tube pin of this inventionare as follows. First, it can be used in a one-step procedure, insteadof requiring pre-drilling of a hole in the tooth structure to receivethe threaded, friction or cementable pins known in the prior art.Second, it eliminates all lateral voids and stresses because it createsits own crypt in the tooth structure and remains in that position. Thus,it eliminates the void between the male and female threads of thethreaded pins known in the prior art which have heretofore providedareas for entrance of impurities. It also eliminates the problemsresulting from incomplete seating of the pins known in the prior art.Third, the end cutting tube pin of this invention eliminates thefracture lines which occur at the threaded areas of dental pins used inthe prior art. It also avoids the incidence of fracture lines in thelateral and base walls of the tooth structure which resulted from thegreater force required to seat the tapered friction pins of the priorart. The reinforcing rods can be placed in the tube of this inventionwithout stress of the tooth structure. Fourth, it provides greater easeof placement and positioning. The end cutting blade of this inventioninvolves less cutting surface and thereby reduces friction and heat. Themandrel of this invention is self-limiting thereby allowing properplacement in depth and position. Fifth, the dental pin of this inventionprovides greater strength because it achieves a lateral seal, eliminatesfracture lines and provides air through the tube of the pin. Sixth, itprovides greater durability because the tube pins of this invention bendwithout breaking due to the equal distribution of stress, whereas thesolid pins of the prior art often break while the dentist is trying toposition them within a particular area. Seventh, the dental pins of thisinvention provide a greater adaptability because they may be silverplated to accommodate metallic bonding with silver amalgam. In thealternative, they may be coated with resin to accommodate chemicalattachment to the resins and composites. Eighth, the pins of thisinvention provide a greater spectrum of use in dental care because theyallow all malleable and cast restoration. They allow a one appointmentprocedure. They also allow non-parallel and parallel pin procedures forinlays and splinting.

DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a mutilated tooth beforerestoration in which dental pins of this invention are inserted forpurposes of restoring the tooth.

FIG. 2 illustrates the tooth shown in FIG. 1, after restoration usingthe dental pins of this invention.

FIGS. 3, 4, 5 and 6 show various embodiments of the end cutting tube pinof this invention.

FIGS. 7, 8 and 9 show various embodiments of reinforcing rods of thisinvention designed to be used in conjunction with the pins shown inFIGS. 3, 4 and 5.

FIG. 10 shows a typical assembly of the dental pin, bushing, mandrel andreinforcing rod of this invention and a dental hand piece.

FIGS. 11, 12, 13 and 14 show additional embodiments of the end cuttingtube pins of this invention.

FIG. 15 is an end view of FIG. 11.

FIG. 16 is an end view of FIG. 12.

FIGS. 17, 18 and 19 show additional embodiments of reinforcing rods ofthis invention designed for use with end cutting tube pin illustrated inFIGS. 6, 11 and 13.

FIGS. 20, 21 and 22 show various embodiments of a latch type mandreldesigned for use with the dental pins of this invention.

FIG. 23 is an end view of the mandrel shown in FIG. 20.

FIG. 24 is an end view of the mandrel shown in FIG. 21.

FIG. 25 is an end view of the mandrel shown in FIG. 22.

FIGS. 26 and 27 illustrate bushings adapted for use with the mandrels ofthis invention.

FIG. 28 is an end view of the bushing shown in FIG. 26.

FIG. 29 is an end view of the bushing shown in FIG.

FIGS. 30, 31 and 32 illustrate additional embodiments of mandrelsadapted for use with the dental pin of this invention.

FIG. 33 is an end view of the mandrel shown in FIG. 30.

FIG. 34 is an end view of the mandrel shown in FIG. 31.

FIG. 35 is an end view of the mandrel shown in FIG. 32.

FIG. 36 shows the dental pin dispenser of this invention as a completeassembly.

FIG. 37 shows the dental pin dispenser of FIG. 36 disassembled into itsthree major components.

FIGS. 38 and 39 show one of the major components, the main housing, ofthe dental pin dispenser shown in FIG. 37.

FIG. 40 shows an end view of FIG. 38 along the lines A--A.

FIG. 41 shows an end view of FIG. 38 along the lines BB.

FIGS. 42 and 43 show another of the major components, the pin cartridge,of the dental pin dispenser shown in FIG. 37.

FIG. 44 shows an end view of FIG. 43.

FIGS. 45 and 46 show another major component, the pin activator, of thedental pin dispenser shown in FIG. 37.

FIG. 47 is an end view of FIG. 46 along the lines DD.

FIG. 48 is an end view of FIG. 46 along the lines AA.

FIG. 49 is a cross-sectional view of FIG. 46 along the lines BB.

FIG. 50 is a cross-sectional view of FIG. 48 along the lines CC.

DETAILED DESCRIPTION Dental Pin, Reinforcing Rod and Mandrel FIG. 1illustrates a mutilated tooth 1 and mutilated crown 2 and shows theplacement of three end cutting tube pins 4 of this invention inserted inthe dentin 6 of the crown 2. Two of the three end cutting tube pins 4have reinforcing rods 8 and 10. One of the end cutting tube pins 4 hasan eyelet reinforcing rod 8 inserted into pin 4. Another end cuttingtube pin 4 has an L-shaped reinforcing rod 10 inserted into it.

The dental pins 4 of this invention are called end cutting tube pinsbecause they have a tube-like cylindrical structure, with the typicalhollow opening of a cylinder running from one end of the pin 4 to theother end. A reinforcing rod 8 or 10 may be inserted in the upperportion of the dental pin 4. The pins also have cutting blades at theend which are inserted in the tooth structure.

FIG. 1 also shows the root 11, the pulp canal 14, the enamel 16, and thecemento-enamel junction 18 of the crown 2. FIG. 2 shows the restoredcrown 2 with the end cutting pins 4 and the reinforcing rods 8 and 10covered by the restoration 20.

FIGS. 3 through 6 illustrate different variations of the end cuttingtube pin of this invention. FIG. 3 shows a straight end cutting tube pin3 with a slot 22 in the upper portion of the pin for insertion into thepin mandrel. This pin mandrel will be explained subsequently inreference to FIGS. 11-15. FIG. 4 illustrates a straight end cutting tubepin 4 with a slot 24 for insertion into the pin mandrel and the slot 24has a notch 26 at the bottom of the slot 24 for retention of areinforcing rod. The reinforcing rod will be explained subsequently inreference to FIGS. 7, 8 and 9.

FIG. 5 illustrates a straight end cutting tube pin 5 with a slot 24 andnotch 26 and, in addition, having a plurality of randomly placedhorizontal passageways 28 through the pin for the retention ofrestorative material. FIG. 6 illustrates a straight end cutting tube pin7 with a slot 30 for insertion into the pin mandrel and internal threads32 in the upper portion of the pin to receive a threaded reinforcingrod. The threaded reinforcing rod will be explained subsequently inreference to FIGS. l7, l8 and 19.

Each of the pins 3, 4, 5 and 7 shown in FIGS. 3, 4, 5 and 6 has aplurality of cutting blades 9 at the end of the pin which is to beinserted in the tooth structure.

FIGS. 7, 8 and 9 illustrate different shapes of reinforcing rods 8, 10and 12 of this invention designed for placement in the end cutting tubepins illustrated in FIGS. 3, 4 and 5. FIG. 7 shows an L-shaped solidreinforcing rod 10. FIG. 8 shows a T-shaped solid reinforcing rod 12.FIG. 9 shows an eyelet solid reinforcing rod 8.

The typical assembly illustrated in FIG. 10 shows the use of either theT-shaped reinforcing rod 12 or, in the alternative, the eyeletreinforcing rod 8 in conjunction with straight end cutting tube pin 4.

FIGS. 11 through 14 illustrate additional variations of the end cuttingtube pins of this invention. FIG. 11 illustrates an end cutting tube pin34 which has a flange 35 positioned at approximately the midpoint alongthe length of the pin. Referring to FIG. 15, the flange 35 in thisembodiment has a substantially square shape, but it will be understoodthat the flanges of other embodiments may be designed with a differentshape. Referring to FIG. 11, end cutting tube pin 34 also has aninternal thread 32 and a slot 36.

FIG. 12 illustrates an end cutting tube pin 38 with a slot 40 forinsertion into the pin mandrel and a notch 42 at the bottom of slot 40.End cutting tube pin 38 also has a flange 35 positioned at approximatelythe midpoint along the length of the pin. The flange 35 is square inshape as shown in FIG. 16. End cutting tube pins 34 and 38 having aflange 35 are suitable for use where the tooth structure is flat.

FIG. 13 illustrates an end cutting tube pin 44 having a bellied portion46 for use where the tooth structure warrants such a design. End cuttingtube pin 44 also has a slot 36 and internal threads 32.

FIG. 14 illustrates an end cutting tube pin 48 which also has a belliedportion 46 consisting of a round balllike protuberance, at approximatelythe midpoint along the length of the pin. End cutting tube pin 48 has aslot 40 with a notch 42 at the end of the slot 40.

Each of the dental pins 34, 38, 44 and 48 shown in FIGS. 11, 12, 13 and14 has a plurality of cutting blades 9 at the end of the pin which is tobe inserted in the tooth structure.

FIGS. 17, 18 and 19 illustrate additional reinforcing rods 50, 52 and54, each having a threaded end 56 for insertion in an end cutting tubepin which has internal thread, such as end cutting tube pin 7 shown inFIG. 6, end cutting tube pin 34 shown in FIG. 11, and end cutting tubepin 44 shown in FIG. 13. FIG. 17 shows an L- shaped solid reinforcingrod 50. FIG. 18 shows a T- shaped solid reinforcing rod 52. FIG. 19shows an eyelet solid reinforcing rod 54.

FIGS. 20, 21 and 22 illustrate latch type mandrels adapted for use inpositioning the end cutting tube pins of this invention in the toothstructure of a tooth to be restored.

Each mandrel 60, 62 and 64 is comprised of a base portion 55, 57 and 59,a cylindrical mandrel tube 61, 63 and 65 adapted for receiving a portionof the dental pin in the mandrel tube and. a plunger apparatus 67, 69and 71 for ejecting the dental pin from the mandrel and embedding thepin in the tube structure. The base portions 55 and 57 of mandrels 60and 62 are hollow to allow the insertion of a straight dental pin suchas dental pin 3 of FIG. 3. FIG. illustrates a dental pin mandrel(designated generally by the numeral 60) having an internal bevel 73adapted for receiving an end cutting tube pin 34 and 38 of the typehaving a flange 35 as shown in FIGS. 11 and 12. FIG. 23 is an end viewof mandrel 60 showing the substantially square shape of the bevel 73 forreceiving the flange 35 of the end cutting tube pins 34 or 38.

FIG. 21 illustrates a dental pin mandrel (designated generally by thenumeral 62) which has an internal tongue 75 in its base portion 57adapted to engage the slot of a straight end cutting tube pin such aspins 3, 4, 5 and 7, shown respectively in FIGS. 3, 4, 5 and 6, whichhave a slot 22, 24 and in the upper portion of the pin. FIG. 24 shows anend view of the mandrel 62 of FIG. 21.

FIG. 22 illustrates a pin mandrel (designated generally by the numeral64) which has an internal tongue 75 in its base portion 59, an internalbevel 73 and an enlarged internal hollowed portion 77 adapted forreceiving end cutting tube pins of a type having both flanges and abellied portion (not illustrated). Such an end cutting tube pin is acombination which includes both the flanges of pins 34 and 38 shown inFIGS. 11 and 12 and the bellied portion 46 of pins 44 and 48 shown inFIGS. 13 and 14. FIG. 25 shows an end view of a mandrel 64 of FIG. 22.

FIGS. 26 and 27 illustrate bushings 66 and 68 adapted for use with themandrels of this invention. FIGS. 28 and 29 illustrate end views of therespective bushings 66 and 68. Each bushing 66 and 68 is a shorttube-like cylinder, the outer circumference of which is adapted to fitwithin the mandrel. The inner circumference of the bushings 66 and 68 isadapted to receive the upper portion of a dental pin. Bushing 66 isdimensioned to fit into the base portion of mandrel or the base portion57 of mandrel 62. Bushing 68 is dimensioned to fit into the enlargedhollow portion 77 of base portion 59 of mandrel 64. The use of a bushingis at the option of the dentist where necessary.

FIG. 30 illustrates a mandrel which is similar to mandrel 60 of FIG. 20except that mandrel 70 is adapted for use with a friction grip dentalhand piece (not illustrated). The mandrel 70 is designed for end cuttingtube pins 34 and 38 having flanges 35, shown in FIGS. 11 and 12. FIG. 33is an end view of mandrel 70.

FIG. 31 also illustrates a mandrel 72 which is similar to mandrel 62 ofFIG. 21 except that mandrel 72 is adapted for use with a friction griphand piece (not illustrated). The mandrel 72 is designed for use withstraight end cutting tube pins 3, 4, 5 and 7, shown in FIGS. 3, 4, 5 and6. FIG. 34 is an end view of mandrel 72.

FIG. 32 illustrates a mandrel 74 which is similar to mandrel, 64 of FIG.22 except that mandrel 74 is adapted for use with a friction grip handpiece (not illustrated). The mandrel 74 is designed to be used with endcutting tube pins having both flanges and a bellied portion. FIG. 35 isan end view of mandrel 74.

The typical assembly of the foregoing apparatus illustrated in FIG. 10shows a dental hand piece 76 into which mandrel 62 is placed. Bushing 66may be placed inside of mandrel 62 but the use of a bushing is optional.An end cutting tube pin 4 is then inserted into mandrel 62 for use.After the pin 4 has been positioned in the tooth, a reinforcing rod 8 or12 may be inserted into the tube pin 4, at the discretion of the dentistdepending upon whether or not it is necessary.

Referring to FIGS. 1 and 2, a tooth is prepared in the usual mannerincluding the removal of all carious lesions and undermined enamel,which could possibly entail removal of all cusp and large portions ofthe crown 2 of the tooth. An end cutting tube pin 4 is then placed to adepth of 2 millimeters into the dentin 6 approximately one-halfmillimeter pulpal of the cementoenamel junction 18. After placing thepin or pins 4 into the tooth structure reinforcing rods 8 or 10 may beinserted in the tube pin 4 as shown in FIGS. 1 and 2. The tooth is thenrestored using standard procedures and materials as shown in FIG. 2. Ifthe restoration is amalgam, then a silver plated end cutting tube pin 4for metallic bonding is used. If the restoration 20 is a resin orcomposite, then a resin coated tube pin 4 is used for chemical bondingof the materials.

The end cutting tube pins and pin mandrels may be made of any hardnon-corrosive metal. The bushings may be made of any soft non-corrosivemetal, or teflon or plastic. The reinforcing rod may be made of anydurable non-corrosive metal.

Dental Pin Dispenser FIG. 36 shows the dental pin dispenser 80 as acomplete assembly, which may be used to dispense any one of the types ofdental pins disclosed in this invention. FIG. 37 shows the dental pindispenser disassembled into its three major components: the main housing82, the pin cartridge 84 and the pin activator 86.

FIGS. 38 and 39 illustrate the main housing 82 for the pin dispenser 80(shown in FIG. 36). Referring to FIG. 39, the main housing 82 is anelongated hollow tube and has a piston assembly 88 positioned thereon atone end of the housing 82. The piston assembly 88 has a pin piston 90which is a metal rod that causes a pin to be dispensed. The pin isdispensed downwardly through slot 91 of piston bushing 92 whichcooperates with the piston 90 and has a passageway which is dimensionedto allow a pin to pass through the passageway 85. The dental pin remainsat all times in a vertical position. While in vertical position, the pinmoves horizontally through passageway 85 and vertically down throughslot 91.

A lever arm 94 is connected to the pin piston 90. The lever arm 94 isactivated by finger pressure downwardly to cause the piston to lift andallow a pin to be placed in bushing 92. A pinion 96 cooperates in therotation of the lever arm 94 and the pin piston 90. A leaf spring 98 isconnected to the lever arm 94 and maintains the pin piston 90 in alocked configuration at times when the lever arm 94 is not activated toprevent a pin from protruding through bushing 92. The housing 82 has abase slot 83 positioned at the opposite end from the piston assembly 88which slot 83 engages a spring lock 112 of the pin activator 86 shown inFIG. 46.

FIG. 40 shows an end view of the main housing 82 along the lines A-A ofFIG. 38. FIG. 41 shows an end view of the main housing 82 along thelines BB of FIG. 38.

FIG. 42 shows the pin cartridge 84 which is an elongated structure thatcan be adjusted to different sizes to accommodate the desired size pin.FIG. 42 shows a top view of cartridge 84. FIG. 43 shows a side view ofcartridge 84. FIG. 44 shows an end view of cartridge 84. The dental pinsare placed in a vertical position within cartridge 84 and movehorizontally along cartridge channel 87.

FIG. 45 illustrates the pin activator 86. Cap 102 retains the pinactivator 86 in the main housing 82. The expansion spring 106 maintainspressure against the cap 102 and against the pin controller 108. Thespring rod 104 is used to stabilize and guide the expansion spring 106and the spring rod 104 is calibrated in order to reflect the number ofpins left in the cartridge 84 of the pin dispenser 80. (See FIG. 36) Thepin controller 108 fits in the two elongated vertical arms 110 of thepin cartridge 84 shown in FIG. 44.

Referring to FIGS. 46 and 48, there is a spring lock 112 which preventsthe pin activator 86 from forcing itself out of the housing 82. Thespring lock 112 is an appendage from cap 102 which fits into the baseslot 83 of the housing 82 shown in FIG. 39.

Referring to FIGS. 46 and 49, a spring washer 114 is attached to the pincontroller 108. Referring to FIG. 49, the slot positioner 116 is used tomaintain the proper position of the pins in the pin cartridge 84. Theslot positioner 116 is used in conjunction with the pin controller 108and is either an integral part of the pin controller 108 or is attachedto the pin controller 108. Referring to FIG. 50, which shows acrosssectional view of FIG. 48 along the lines CC, there is a bore 117in cap 102 through which the spring rod 104 (shown in FIGS. 45, 47 and36) may protrude.

Referring to FIG. 37, dental pins are loaded into cartridge 84. Then thecartridge 84 is inserted into housing 82, after which activator 86 ispositioned and locked in housing 82. With reference to the position ofthe cartridge 84 as shown in FIG. 37, when the pins are within cartridge84 they move in a direction from left to right within cartridge 84. Thepins are ejected from the pin dispenser by the activation of pistonassembly 88.

In the foregoing description, the invention has been described inreference to specific exemplary embodiments. However, variations andmodifications may be made without departing from the broader scopeandspirit of the invention as set forth in the appended claims. Thespecification and drawings are accordingly to be regarded in anillustrative rather than in a restrictive sense.

What is claimed is:

1. An end cutting dental pin which combines cutting and structuralelements for use in the reconstruction of a mutilated tooth, the dentalpin being adapted sequentially to cut the tooth material of theremaining portion of a mutilated tooth and thereafter to becomepermanently embedded in and retained as a structural element of thereconstructed tooth, the pin being further adapted for insertion intothe remaining portion of a mutilated tooth by the use of a pin mandrel,and comprising a cylindrical structural element which integrallyincludes:

a. a plurality of passagewqys through the cylindrical structural elementfor the retention of restorative material;

b. cutting blades disposed at one end of the cylindrical element, thecutting blades being adapted for cutting a hole in tooth material in theshape and size sufficient to allow the penetration of the pin into themutilated tooth; and

c. engagement means upon the cylindrical element to allow the temporaryengagement of the element with a pin mandrel during the cutting of ahole by the blades and the penetration of the pin into the toothmaterial.

2. A dental pin combining cutting and structural elements adapted to beembedded in the structure of a mutilated tooth which is reconstructed,the dental pin being adapted for insertion in the mutilated tooth by theuse of a pin mandrel and comprising:

a. a straight tube-like cylindrical structural element adapted forreception into a mutilated tooth and retention in a reconstructed tooth,the cylindrical element including a slot in the upper portion thereof,the slot being adapted for engagement of the pin mandrel when the pin isinserted in the mandrel, the cylindrical element further includinginternal threads in the upper portion of the cylindrical element, saidthreads being adapted to receive a threaded reinforcing rod; and

b. cutting blades adapted for cutting tooth material, the blades beingincluded in the cylindrical element and being disposed at the end of thecylindrical element which is driven into the mutilated tooth by the useof a pin mandrel.

3. A dental pin combining cutting and structural elements adapted to beembedded in the structure of a mutilated tooth which is reconstructed,the dental pin being adapted for insertion in the mutilated tooth by theuse of a pin mandrel and comprising:

a. a tube-like cylindrical structural element adapted for reception intoa mutilated tooth and retention in a reconstructed tooth, the tube-likecylindrical structural element further including a bellied portionconsisting of a round ball-like protuberance at approximately themidpoint along the length thereof; and

b. cutting blades adapted for cutting tooth material, the blades beingincluded in the cylindrical element and being disposed at the end of thecylindrical element which is driven into the mutilated tooth by the useof a pin mandrel.

4. A dental pin combining cutting and structural elements adapted to beembedded in the structure of a mutilated tooth which is reconstructed,the dental pin being adapted for insertion in the mutilated tooth by theuse of a pin mandrel and comprising:

a. a tube-like cylindrical structural element adapted for reception intoa mutilated tooth and retention in a reconstructed tooth, the tube-likecylindrical element including:

i. a slot in the upper portion of the element which is adapted forengagement of a pin mandrel when the pin is subsequently inserted intothe mandrel;

ii. a flange positioned at approximately the midpoint along the lengthof the cylindrical element; and

iii. internal threads in the upper portion of the tube-like cylindricalelement, said threads therein being adapted to receive a threadedreinforcing rod; and

b. cutting blades adapted for cutting tooth material, the blades beingincluded in the cylindrical element and being disposed at the end of thecylindrical element which is driven into the mutilated tooth by the useof a pin mandrel.

5. A dental pin combining cutting and structural elements, the dentalpin being adapted to be embedded in the structure of a mutilated toothwhich is reconstructed, the dental pin further being adapted forinsertion in the mutilated tooth by the use of a pin mandrel andcomprising:

a. a tube-like cylindrical structural element adapted for reception intoa mutilated tooth and retention in a reconstructed tooth;

b. cutting blades adapted for cutting tooth material, the blades beingincluded in the cylindrical element and being disposed at the end of thecylindrical element which is driven into the mutilated tooth by the useof a pin mandrel;

c. a slot in the upper portion of the cylidrical element which slot is aapted for engagement of a pin mandrel when the dental pin is insertedinto the mandrel; and

d. a bellied portion consisting of a round ball-like protuberance atapproximately the midpoint along the length of the cylindrical element.

6. A dental pin according to claim and further including a notch at thebottom of the slot in the upper portion of the dental pin, said notchbeing adapted for engagement of the pin mandrel when the dental pin issubsequently inserted in the mandrel.

7. A dental pin according to claim 5 and further including internalthreads in the upper portion of the pin, said threads being adapted toreceive a threaded reinforcing rod.

8. A dental pin combining cutting and structural elements, the dentalpin being adapted to be embedded in the structure of a mutilated toothwhich is reconstructed and being further adapted for insertion in themutilated tooth by the use of a pin mandrel and comprising: l

a. a tube-like cylindrical structural element adapted for reception intoa mutilated tooth and retention in a reconstructed tooth, thecylindrical structural element including therein, a separately formedreinforcing rod adapted to be inserted in the upper portion of thecylindrical structural element after said cylindrical structural elementis inserted in the tooth; and

b. cutting blades adapted for cutting tooth material, the blades beingincluded in the cylindrical element which is driven into the mutilatedtooth by the use of a pin mandrel.

9. A dental pin according to claim 8 in which the reinforcing rodextends beyond the end of the upper portion of the cylindrical element.

10. A dental pin according to claim 9 wherein the portion of thereinforcing rod which extends beyond the upper portion of thecylindrical element is L- shaped.

11. A dental pin according to claim 9 wherein the portion of thereinforcing rod which extends beyond the upper portion of thecylindrical element is T- shaped.

12. A dental pin according to claim 9 wherein the portion of thereinforcing rod which extends beyond the upper portion of thecylindrical element is eyeletshaped.

13. A dental pin combining cutting and structural elements, the dentalpin being adapted to be embedded in the structure of a mutilated toothwhich is reconstructed and being further adapted for insertion in themutilated tooth by the use of a pin mandrel, and comprising:

a. a tube-like cylindrical structural element having internal threads inthe upper portion thereof and being adapted for reception into amutilated tooth and retention in a reconstructed tooth,

b. cutting blades adapted for cutting tooth material comprising amultiplicity of vertically disposed cutting edges, the blades beingincluded in the lower portion of the cylindrical element which is driveninto the mutilated tooth by the use of a pin mandrel; and

c. a separately formed externally threaded reinforcing rod havingthreads corresponding to the internal threads of the upper portion ofthe cylindrical element which is received into the tooth, thereinforcing rod being adapted to be engaged into the cylindrical elementafter the cylindrical element is first inserted and secured in thetooth.

1. An end cutting dental pin which combines cutting and structuralelements for use in the reconstruction of a mutilated tooth, the dentalpin being adapted sequentially to cut the tooth material of theremaining portion of a mutilated tooth and thereafter to becomepermanently embedded in and retained as a structural element of thereconstructed tooth, the pin being further adapted for insertion intothe remaining portion of a mutilated tooth by the use of a pin mandrel,and comprising a cylindrical structural element which integrallyincludes: a. a plurality of passagewqys through the cylindricalstructural element for the retention of restorative material; b. cuttingblades disposed at one end of the cylindrical element, the cuttingblades being adapted for cutting a hole in tooth material in the shapeand size sufficient to allow the penetration of the pin into themutilated tooth; and c. engagement means upon the cylindrical element toallow the temporary engagement of the element with a pin mandrel duringthe cutting of a hole by the blades and the penetration of the pin intothe tooth material.
 2. A dental pin combining cutting and structuralelements adapted to be embedded in the structure of a mutilated toothwhich is reconstructed, the dental pin being adapted for insertion inthe mutilated tooth by the use of a pin mandrel and comprising: a. astraight tube-like cylindrical structural element adapted for receptioninto a mutilated tooth and retention in a reconstructed tooth, thecylindrical element including a slot in the upper portion thereof, theslot being adapted for engagement of the pin mandrel when the pin isinserted in the mandrel, the cylindrical element further includinginternal threads in the upper portion of the cylindrical element, saidthreads being adapted to receive a threaded reinforcing rod; and b.cutting blades adapted for cutting tooth material, the blades beingincluded in the cylindrical element and being disposed at the end of thecylindrical element which is driven into the mutilated tooth by the useof a pin mandrel.
 3. A dental pin combining cutting and structuralelements adapted to be embedded in the structure of a mutilated toothwhich is reconstructed, the dental pin being adapted for insertion inthe mutilated tooth by the use of a pin mandrel and comprising: a. atube-like cylindrical structural element adapted for reception into amutilated tooth and retention in a reconstructed tooth, the tube-likecylindrical structural element further including a bellied portionconsisting of a round ball-like protuberance at approximately themidpoint along the length thereof; and b. cutting blades adapted forcutting tooth material, the blades being included in the cylindricalelement and being disposed at the end of the cylindrical element whichis driven into the mutilated tooth by the use of a pin mandrel.
 4. Adental pin combining cutting and structural elements adapted to beembedded in the structure of a mutilated tooth which is reconstructed,the dental pin being adapted for insertion in the mutilated tooth by theuse of a pin mandrel and comprising: a. a tube-like cylindricalstructural element adapted for reception into a mutilated tooth andretention in a reconstructed tooth, the tube-like cylindrical elementincluding: i. a slot in the upper portion of the element which isadapted for engagement of a pin mandrel when the pin is subsequentlyinserted into the mandrel; ii. a flange positioned at approximately themidpoint along the length of the cylindrical element; and iii. internalthreads in the upper portion of the tube-like cylindrical element, saidthreads therein being adapted to receive a threaded reinforcing rod; andb. cutting blades adapted for cutting tooth material, the blades beingincluded in the cylindrical element and being disposed at the end of thecylindrical element which is driven into the mutilated tooth by the useof a pin mandrel.
 5. A dental pin combining cutting and structuralelements, the dental pin being adapted to be embedded in the structureof a mutilated tooth which is reconstructed, the dental pin furtherbeing adapted for insertion in the mutilated tooth by the use of A pinmandrel and comprising: a. a tube-like cylindrical structural elementadapted for reception into a mutilated tooth and retention in areconstructed tooth; b. cutting blades adapted for cutting toothmaterial, the blades being included in the cylindrical element and beingdisposed at the end of the cylindrical element which is driven into themutilated tooth by the use of a pin mandrel; c. a slot in the upperportion of the cylidrical element which slot is a apted for engagementof a pin mandrel when the dental pin is inserted into the mandrel; andd. a bellied portion consisting of a round ball-like protuberance atapproximately the midpoint along the length of the cylindrical element.6. A dental pin according to claim 5 and further including a notch atthe bottom of the slot in the upper portion of the dental pin, saidnotch being adapted for engagement of the pin mandrel when the dentalpin is subsequently inserted in the mandrel.
 7. A dental pin accordingto claim 5 and further including internal threads in the upper portionof the pin, said threads being adapted to receive a threaded reinforcingrod.
 8. A dental pin combining cutting and structural elements, thedental pin being adapted to be embedded in the structure of a mutilatedtooth which is reconstructed and being further adapted for insertion inthe mutilated tooth by the use of a pin mandrel and comprising: a. atube-like cylindrical structural element adapted for reception into amutilated tooth and retention in a reconstructed tooth, the cylindricalstructural element including therein, a separately formed reinforcingrod adapted to be inserted in the upper portion of the cylindricalstructural element after said cylindrical structural element is insertedin the tooth; and b. cutting blades adapted for cutting tooth material,the blades being included in the cylindrical element which is driveninto the mutilated tooth by the use of a pin mandrel.
 9. A dental pinaccording to claim 8 in which the reinforcing rod extends beyond the endof the upper portion of the cylindrical element.
 10. A dental pinaccording to claim 9 wherein the portion of the reinforcing rod whichextends beyond the upper portion of the cylindrical element is L-shaped.11. A dental pin according to claim 9 wherein the portion of thereinforcing rod which extends beyond the upper portion of thecylindrical element is T-shaped.
 12. A dental pin according to claim 9wherein the portion of the reinforcing rod which extends beyond theupper portion of the cylindrical element is eyeletshaped.
 13. A dentalpin combining cutting and structural elements, the dental pin beingadapted to be embedded in the structure of a mutilated tooth which isreconstructed and being further adapted for insertion in the mutilatedtooth by the use of a pin mandrel, and comprising: a. a tube-likecylindrical structural element having internal threads in the upperportion thereof and being adapted for reception into a mutilated toothand retention in a reconstructed tooth, b. cutting blades adapted forcutting tooth material comprising a multiplicity of vertically disposedcutting edges, the blades being included in the lower portion of thecylindrical element which is driven into the mutilated tooth by the useof a pin mandrel; and c. a separately formed externally threadedreinforcing rod having threads corresponding to the internal threads ofthe upper portion of the cylindrical element which is received into thetooth, the reinforcing rod being adapted to be engaged into thecylindrical element after the cylindrical element is first inserted andsecured in the tooth.